Auxiliary contact switch



May 7, 1957 L. H. MATTHIAS AUXILIARY CONTACT SWITCH Filed Aug. 6, 1 953*4 Baal-mega 2 Sheets-Sheet 2 INVENTOR ATTORNEY United States Patent2,791,659 AUXILIARY CONTACT SWITCH Lynn H. Matthias, Fox Point, Wis.,assignor to Allen- Bradley Company, Milwaukee, Wis., a corporation ofWisconsin Application August 6, 1953, Serial No. 372,649 11 Claims. (Cl.200-104) This invention relates to electrical switches having a set ofmain contacts for opening and closing a power circuit and additionalauxiliary contacts suitable for completing and interrupting controlcircuits carrying lesser currents and it more specifically resides in aswitch having an actuator reciprocatably movable through a strokeextending between a position of rest and an actuated position foreifecting engagement and disengagement of a set of main contacts and adisplaceable member supporting movable auxiliary contact means that hasa portion disposed in the path of travel of said actuator to be movedtherewith to engage and disengage said movable auxiliary contact meanswith stationary auxiliary contact means that are provided.

Electro-magnetic switches as employed for starting and stopping electricmotors are frequently employed to open and close circuits in addition tothose required for the control of the associated motor. This requiresthe provision of additional auxiliary contacts and it is particularlydesirable to adapt a switch of standardized form to such applicationsrequiring additional contacts without resort to extensive alteration ofthe switch. Such adaptation alleviates the necessity of the manufactureof special switches that would otherwise entail large additionalexpense.

It is an object of this invention to provide for the addition ofcontacts to a switch as the need arises without alteration of theswitch, to enhance the versatility of application of the switch tovarying circuit requirements.

It is another object of this invention to provide auxiliary contacts fora switch in addition to power circuit contacts that have a double breakupon disengagement.

It is another object of this invention to provide auxiliary contacts fora switch in addition to power circuit contacts with a self wipingaction.

It is a further object of this invention to provide sets of detachableauxiliary contacts for a switch in which each set is separately housedwithin a protective chamber.

It is still another object of this invention to provide a switch forcontrol of power circuits that may have additional auxiliary contactsmounted thereon to be operated by the actuator for the power circuitcontacts, which auxiliary contacts may be mounted in assembled sets byfastening with simple screw means.

These and other objects and advantages of this invention will appear inthe description to follow. In the description reference is made to theaccompanying drawings, which form a part hereof, and in which there isshown by way of illustration and not of limitation a specific form inwhich the invention may be embodied.

In the drawings:

Fig. 1 is a front view in elevation with parts broken away and insection of an electro-magnetic switch embodying this invention,

Fig. 2 is a fragmentary view in section of the switch viewed through theplane 2-2 indicated in Fig. 1,

Fig. 3

is a diagram illustrating the sequence of contact engagement that occursin the stroke of the armature of the switch shown in Fig. 1,

Fig. 4 is a rear view in elevation of an auxiliary contact assembly thatforms a part of the switch shown in Fig. 1,

Fig. 5 is a view in section of the auxiliary contact assembly shown inFig. 4 viewed through the plane Fig. 6 is a fragmentary view in sectionof the auxiliary contact assembly viewed through the plane 6-6 indicatedin Fig. 4,

Fig. 7 is a view in section of the auxiliary contact assembly viewedthrough the plane 7-7 indicated in Fig. 4,

Fig. 8 is a rear view in elevation of a second auxiliary contactassembly that forms a part of the switch shown in Fig. l, and

Fig. 9 is a view in perspective of a terminal for a stationary auxiliarycontact employed in the auxiliary contact assembly shown in Figs. 4-7.

Referring now to the drawings, there is shown an electro-magnetic'switch 1 having a vertical mounting plate 2 with a plurality of openings3 suitable for securing the switch 1 to a panel or the like. Fastened tothe plate 2 by rivets 4 is a field piece 5 comprising a rear bracket 6,held by the rivets 4, and a front plate 7, between which a set ofstacked laminations 8 is held tightly compressed by rivets 9. A coil 10having a central vertical opening is supported within the laminations 8and an inverted T-s'haped armature 11 is disposed with its transverseportion 12 beneath the laminations 8, and with its shank extendingupwardly and received within the central opening of the coil 10 forlimited vertical travel. The transverse portion 12 of the armature ithas upwardly facing pole faces 13 disposed to seat against downwardlyfacing pole faces 14 of the lamina tions 8 upon energization of the coil10. A set of shading coils 15 are embedded in the pole faces 14 for theusual purposes.

An armature tongue 16, shown in Fig. 2, extends upwardly beyond theshank through a slot in the laminations 8. Secured to the tongue 16 by apair of screws 17 is a cross bar 18 of molded insulating material thatextends on both sides of the armature 11 and rests upon the laminations8 to limit the downward travel of the armature when the coil 10 isdeenergized.

A set of four uniformly spaced T-shaped inserts 19 project upwardly fromthe cross bar 18, and a main bridging contact 20 that is free to moveupwardly and downwardly relative to the cross bar 18 is held captive byeach of the inserts 19. A fiat strip coil spring 21 encircles eachinsert 19 and is disposed beneath the respective bridging contact 20 tourge the respective contact 20 upwardly, to maintain contact pressure inthe manner hereinafter described.

The rear bracket 6 supports a molded hood 22 with a vertical rear wall23 from the end margins of which a pair of side walls 24 extendforwardly. Evenly spaced between the side walls 24 are three verticalpartitions 25 that divide the interior of the hood 22 into four contactchambers. A ceiling 26 and a front wall 27 that extends between theforward margins of the end walls 24 and the partitions 25 complete thehood 22 which is an open bottomed enclosure into which the bridgingcontacts 20 are moved.

A set of four angularly shaped rear terminals 28 are secured to theupper face of the ceiling 26 by bolts 29 and nuts 30. The head of eachbolt 29 has mounted thereon a stationary main contact 31 that is infacing relation to a bridging contact 20. A set of four forwardterminals 32 are secured to the upper face of the ceiling 26 in front ofthe rear terminals by means of bolts 33 and nuts 34. Each bolt 33 has ahead that mounts a stationary main contact 35 in facing relation to abridging contact 26. The stationary contacts 31 and 35 are paired, eachpair being separated from adjacent pairs by a partition 25 and beingdisposed to be connected by a bridging contact 20 upon movement of thearmature 11 and cross bar 18 upwardly in response to energization of thecoil 10. I r

A pair of auxiliary contact housings 36 and 37 of molded insulatingmaterial are mounted on the front wall 27 of the hood 22 by means ofmounting screws 38 that are thread'edly received in the forwardterminals 32. Each housing 36, 37 extends downwardly along the frontface 27 and turns rearwardly beneath the hood 22. The housing 36, whichis shown in Figs. 4-7, has a lower portion in the form of a contactenclosure 39 having a pair of side walls 40, a top cover 41 and a floor42. The rear of the enclosure 39' is open and a slotted central verticalrib 43 divides the front into a pair of right and left hand openings 4.4. A right hand terminal 45 is inserted in the right hand opening 44,as viewed from the rear in Fig. 4, and a left hand terminal 46 isinserted in the left hand opening 44. The terminals 45 and 46 each fullyclose the respective openings 44 to form a front wall for the enclosure39.

The terminal 45 is of the configuration shown in Fig. 9, where itappears that a vertical web 47 threadedly receives a terminal screw 43and an upper flange 49 having a threaded opening 50 extends from the topmargin of the web 47. From the bottom margin of the web 47 a lowerflange 53 with a threaded opening 61 extends beneath the flange 49 andhas a finger 52 in the form of a continuing extension upon which ismounted a stationary auxiliary contact 53. One corner of the upperflange 49 has a sharply beveled edge 54 and the lower flange 51 has asim'larly beveled edge 55 that continues along the finger 52'. Due tothe bevel the contact 53' is offset at one side of the center of theterminal 45, as clearly shown in Fig. 4. The terminal 46 is similar tothe terminal 45, with the exception that the sharply beveled edges areat the opposite sides of the upper and lower flanges, and the contact 56of the terminal 46 is ofiset on the opposite side of the terminal centerline, as is clearly shown in Figs. 4 and 7. Upon insertion of theterminals 45 and 46 into the enclosure 39 the beveled edges 54, 55 ofthe terminal 45 will engage mating ridges in the enclosure 39 one ofwhich is shown at 57 in Fig. 7, and the similarly beveled edges of theterminal 416 will strike similar mating ridges, one of which is shown at53; The end of the upper flange 49 strikes the ridge 59, shown in Figs.4 and 7 to limit the extent of the insertion of the terminal 45, andsimilarly the terminal 46 strikes a ridge 6d, shown in Figs. 4 and 6;Each of the terminals 45, 46 is secured inposition by a mounting screw62 passing upwardly through the floor 42 and received in the threadedopening 6%.

One end of an actuating lever 63 is inserted in the slotted central ribof the housing 36 and is pivoted on a pin 64. The lever 63 extendsrearwardly between the stationary terminals 45, 46 to project from thehousing 36 with a displaceable end 65 overhanging the contact cross bar18, as shown in Fig. 2. A spring 66 is disposed between a spring seat6"!" on the upper side of the lever 63 and asecond spring seat 6 3formed in the housing 36 to mo e the lever 63 to its lower position asshown in Fig. 5. An opening 69 in the body of the lever 63 receives aresilient bridging contact arm 70 that mounts a movable auxiliarycontact 71 at each end in facing relation to a stationary auxiliarycontact. A spring 72 also is inserted in the opening 69 with its lowerend held by an ear '73 and its upper end pressing upwardly upon theunderside of the bridging contact arm 70.

Referring now to Fig. 8, there is shown the auxiliary contact housing37, which is identical with the housing, 36 and which has likedesignating reference numerals for like parts. The'actuating'lever inthe housing 37 and the parts attached and engaged therewith are alsolike those of the housing 36 and like designating reference numeralshave been applied to the parts shown. Inserted in the housing 37 areterminals indicated by reference numerals 45 and 46, being similar tothe terminals 45 and 46, but differing from them in that they areinverted and their associated auxiliary contacts 53 and 56 are disposedabove the movable auxiliary contacts 71. This manner of insertion of theterminals 45 and 46 in the housing 37 is ina sense the opposite of thatemployed in the housing 36. The terminal 45' is inserted in the lefthand opening 44, as viewed in Fig. 8, whereas the terminal 45 isinserted in the right hand opening 44 of the housing 36 and the mountingscrew 62 for the terminal 45 is threadedly engaged with the flange 49'.Similarly the terminal 46 is inserted in the right hand opening 44 andretained by an associated screw 62. It is possible to thus provide anormally open set of aux-iliary contacts as distinguished from thenormally closed contacts of the housing 36, simply through rearrangementof parts. A right hand terminal 45 is converted to a left hand terminal45 simply by inversion. Likewise terminal 46 is converted to terminal46'. V

In Fig. 3, the vertical line 74 represents the stroke of the armature 11and cross bar 18 in moving between the position of rest shown in Fig. 1in which the underside of the cross bar 18 rests upon the laminations 8,and the energized position in which the pole faces 13 of the armature 11seat against the pole faces 14 of the field piece 5. As the armature 11is moved upwardly in response to ener'gization of the coil 10 the crossbar 18 will strike and pick up the displaceable ends 65 of the levers 63at a point in the stroke corresponding to the line 75. Continued upwardtravel of the cross bar 18 swings the levers 63 about the pivot pins 64and the normally closed auxiliary contacts in the housing 36 will openat a point in the stroke corresponding to the line 76. Next, the crossbar 18 moves the main bridging contacts 20 into engagement with the mainstationary contacts 31, 35 at a point in the stroke corresponding to theline 77. The coil springs 21 are compressed between the contacts 29 andthe upwardly traveling cross bar 18 to provide contact pressure. Furthertravel of the cross bar 18 moves the lever 62 of the housing 37 toengage the normally open auxiliary contacts at a point 78 in the stroke.The spring 72 in the housing" 37 then becomes compressed to provideContact pressure and thereafter the armature 11 travels a sufficientdistance to provide ample compression of springs 21 and 72 before thepole faces 13 seat against the'pole' faces 14 of the field piece 5.

Upon deenergization of the coil 14) the armature 11 drops to thenormal'position of rest shown in Fig. 1. The sequence of contactdisengagement and engagement will be'the reverse of that described forarmature pickup. The normally open auxiliary contacts of the housing 37open, followed by opening of the main contacts and then closure of thenormally closed auxiliary contacts of the housing 36. As the normallyclosed contacts in the housing 36 are brought into engagement thebridging contact arm 79 assumes a bowed position, as in Fig. 4; toprovide contact pressure and a wiping action of the contacts will occur.A similar wiping action will occur upon closure of the normally opencontacts of the housing 37, due to the resiliency of the contact arm 70.

Additional auxiliary contact housings such as 36, 37'

may be secured to the hood 22 if desired. Or, either or both of thehousings 36, 37 may be removed. Thus' a switch primarily adapted for theopening and closing of power circuits through main contacts such as 20,31 and 35 may be employed to control additional circuits without resortto alteration or modification of the elements comprising the switch.Versatility is further en'- hanced by the provision of auxiliary contactassemblies which maybe arranged for either normally open or nor mallyclosed operation by a simple inversion of the terminals.

I claim:

1. In a switch the combination comprising a support carrying a set offixed main contacts, a set of movable main contacts, an actuator forsaid movable main contacts adapted to move between contact open andcontact closed positions, an auxiliary contact housing secured to saidsupport, a lever having one end pivoted to said housing and extendingtherefrom to terminate in a displaceable end disposed within the path ofmovement of said actuator to be displaced thereby from a positioncorresponding to the contact open position of said actuator upon saidactuator moving from said contact open position toward said contactclosed position, said lever including an opening medial its pivoted anddisplaceable ends, a bias spring retained by said housing acting uponsaid lever to move the lever to the position corresponding to thecontact open position of said actuator, a pair of stationary auxiliarycontacts within said housing disposed on opposite sides of said lever, aresilient deflectable bridging contact arm inserted through the openingof said lever in bridging relation to said stationary auxiliary contactsto be engaged and disengaged therewith upon movement of said lever, anda spring hearing at one end upon said bridging contact arm urging thearm against one end wall of the opening of said lever and bearing at itsother end against an opposite wall of the opening.

2. In a switch the combination comprising a support with a set of fixedmain contacts, a set of movable main contacts, an actuator for saidmovable main contacts adapted to move between contact open and contactclosed positions, an auxiliary contact housing secured to said supporthaving a contact chamber substantially closed on both sides, the top andthe bottom, a lever having one end pivoted to said housing and extendingtherefrom to terminate in a displaceable end disposed within the path ofmovement of said actuator to be displaced thereby from a positioncorresponding to the contact open position of said actuator upon saidactuator moving from said contact open position toward said contactclosed position, a bias spring retained by said housing acting upon saidlever to move the lever to'the position corresponding to the contactopen position of said actuator, a pair of terminals each detachablysecured to said housing and having a front web to enclose the front ofsaid chamber and a stationary contact finger extending from a margin ofsaid web within said chamber along a chamber wall, said terminals eachbeing reversible in position to be secured to said housing with saidcontact fingers alongside the bottom chamber wall or in an alternativeposition with said contact fingers alongside the top chamber wall, and aresilient bridging contact arm carried by said lever in bridgingrelation to said stationary auxiliary contacts to be engaged anddisengaged therewith upon movement of said lever.

3. In a switch the combination comprising a contact mounting having aset of stationary main contacts which includes a front, sides and a topand is open at the bottom to receive movable contacts and an actuatortherefor, a main contact actuator extending through the open bottom ofthe contact mounting with a set of movable main contacts in facingrelation to said stationary main contacts having a normal position ofrest and movable through a reciprocatable stroke in which said movablemain contacts are engaged with and disengaged from said stationary maincontacts at a point of travel medial the ends of the stroke, anauxiliary contact support with an upper attachment portion adapted to besecured to the front of said contact mounting and a depending portionturning beneath the front of the contact mounting, a lever pivoted tosaid auxiliary contact support having a displaceable end extendingrearwardly from the depending portion thereof to within the path oftravel of said main contact actuator to be displaced therewith as itmoves through its stroke from said normal position of rest, a biasingspring cooperatively engaged with said lever urging the same to followsaid actuator as it moves in its stroke toward said normal position ofrest to a position of rest corresponding to the position of rest of saidactuator, a movable auxiliary contact mounted on said lever, andterminal means adapted to be secured to the depending portion of saidauxiliary contact support having a stationary auxiliary contact that maybe disposed to one side of said movable auxiliary contact to be engagedthereby upon movement of said lever with said actuator from the positionof rest to a position in the stroke beyond that at which said maincontacts engage, which terminal means may in the alternate be disposedwith said stationary auxiliary contact to the opposite side of saidmovable auxiliary contact to be engaged therewith when said lever is insaid position of rest and disengaged therewith upon movement of saidlever with said actuator against said biasing spring at a point in thestroke before engagement of said main contacts.

4. in a switch the combination comprising a contact hood open at thebottom which has a set of stationary main contacts; an actuator beneaththe open bottom of the contact hood having a position of rest andmovable in a stroke away from and back toward said position of rest; aset of movable main contacts mounted on said actuator in facing relationto said stationary main contacts and engaged and disengaged therewith ata position in the stroke of said actuator medial the position of restand the position at the opposite end of the stroke; an insulatingsupport with an upper attachment portion adapted to be fastened to thehood and a depending portion extending downwardly and turning beneaththe hood; a lever supported by the insulating support having adisplaceable end in the path of travel of said actuator to be displacedthereby; biasing means mounted by said insulating support for said leverurging the displaceable end toward the position of rest of saidactuator; a bridging contact having deflectable resilient arms supportedby said lever, a spring retained at one end by said lever and workingagainst said bridging contact at its opposite end to normally hold saidbridging contact against a portion of said lever and permitting saidbridging contact to move against said spring; and a set of stationaryauxiliary contacts mounted by the depending portion of the insulatingsupport in facing relation with said bridging contact to be connectedthereby and disconnected therefrom upon said actuator moving through itsstroke.

5. In a switch the combination comprising a contact hood open at thebottom which has a set of stationary main contacts; an actuator beneaththe open bottom of the contact hood having a position of rest andmovable in a stroke away from and back toward said position of rest; aset of movable main contacts mounted on said actuator in facing relationto said stationary main contacts and engaged and disengaged therewith ata position in the stroke of said actuator medial the position of restand the position at the opposite end of the stroke; an insulatingsupport with an upper attachment portion adapted to be fastened to thehood and a depending portion extending downwardly and turning beneaththe hood; a lever supported by the insulating support having adisplaceable end in the path of travel of said actuator to be displacedthereby; biasing means mounted by the insulating support for said leverurging the displaceabie end toward the position of rest of saidactuator; a stop on said insulating support limiting movement of saidlever in response to said biasing means to fix a position of rest forsaid lever with the displaceable end thereof spaced from the position ofrest of said actuator; a bridging contact having resilient arms receivedby said lever, a spring seated at one end by said lever and workingagainst said bridging contact at its opposite end to normally hold saidbridging contact against a portion of said lever and permitting saidbridging contact to move against said spring; and a set of stationaryauxiliary contacts mounted by the insulating support in facing relationwith said bridging contact to be connected thereby and disconnectedtherefrom upon said actuator moving through its stroke, said stationaryauxiliary contacts being disposed in a position to be engaged uponmovement of said lever with said actuator from the position of rest to aposition in the stroke beyond that at which said main contacts engage,or in the alternative, in a position to be engaged with said bridgingcontact when said lever is in said position of rest and disengagedtherewith upon movemnet of said lever to a point in the stroke beforeengagement of said main contacts.

6. In a detachable auxiliary contact switch for a main switch withstationary and movable contacts and an actuator for causing contactengagement and disengagement, the combination comprising an insulatingsupport adapted to be detachably secured to such a main switch formed toprovide a pair of contact compartments with orientating surfaces; a pairof terminals each adapted to be inserted within either of said contactcompartments and having a web with an exposed connector for affordingelectrical connection, a pair of upper and lower flanges extending fromthe top and bottom margins of the Web into the respective compartment, afixed contact mounted on one flange facing the opposite flange, andorientation surfaces engageable with the orientating surfaces of therespective compartment for positioning the terminal with respect to thecompartment whereby said terminals may be inverted to dispose therespective contacts toward the bottom or in the alternative toward thetop of the compartments; attachment means received by each of saidcompartments and engageable with a flange of each terminal to fix thesame in position; a lever pivoted at one end to said support andextending therefrom to be actuated by the actuator of a main switch uponattachment of said support thereto; and a bridging contact carried bysaid lever with contact arms in facing relation to the contacts of saidterminals for engagement and disengagement therewith.

7. In a detachable auxiliary contact switch for a main switch withstationary and movable contacts and an actuator for causing contactengagement and disengagement, the combination comprising an insulatingsupport adapted to be detachably secured to such a main switch providinga housing closed at the sides, top and bottom and having right and lefthand compartments; a pair of terminals adapted to be secured to saidinsulating support each having a web enclosing the front of onecompartment, a pair of flanges within the respective compartment thatextend from the top and bottom of the web, and a fixed contact mountedon one flange of the terminal facing toward the other flange, saidterminals being reversible in position whereby each may be inverted andplaced in the opposite compartment to dispose the respec tive contactstoward the bottom or in the alternative toward the top of thecompartments; attachment means through the bottom of said housingsecuring the lowermost flange of each terminal to the housing; a leverpassing through the interior of the housing separating the same intosaid right and left compartments pivoted at one end to said support andextending therefrom to be deflected at the opposite end by the actuatorof a main switch upon attachment of said support thereto; and a bridgingcontact member carried by said lever at a point between the ends thereofwith resilient deflectable contact arms extending into each compartmentfor engagement and disengagement with said terminal contacts.

8. in a detachable auxiliary contact switch for a main switch withstationary and movable contacts and an actuator for causing contactengagement and disengagement the combination comprising an insulatingsupport adapted to be detachably secured to such a main switch with a paof horizontally spaced right and left hand terminal receiving portions,each portion presenting terminal orientating surfaces; a first terminalincluding a central web with top and bottom margins, a flange extendingfrom one margin of said web with a fixed contact offset to one side ofthe terminal and orientation surfaces adapted to mate with theorientating surfaces of said insulating support whereby said terminalmay be inserted in either the right or left hand terminal receivingportion but is restricted such that an inversion is required when beingtaken from one portion and placed in the other whereby said contact isdisposed toward the top and the outside when in the right hand terminalreceiving portion and toward the bottomand outside when in the left handterminal receiving portion; a second terminal including a central webwith top and bottom margins, a flange extending from one margin of saidweb with a fixed contact olfset to one side of said terminal, andorientation surfaces forming a part of said terminal adapted to matewith the orientating surfaces of said insulating support whereby saidterminal may be inserted in either the right or left hand terminalreceiving portion but is restricted such that an inversion is requiredwhen being taken from one portion and placed in the other whereby saidcontact is disposed toward the bottom and outside when in the right handterminal receiving portion and toward the top and outside when in theleft hand terminal receiving portion; attachment means adapted to retainsaid terminals in orientated position with respect to said terminalreceiving portions of said support; an operating member carried by saidsupport and extending therefrom to be actuated by the actuator of a mainswitch upon attachment of said support thereto; and a deflectablebridging contact arm carried by said operating member extending betweenthe contacts of said terminals for engagement and disengagementtherewith.

9. in a detachable auxiliary contact switch for a main switch withstationary and movable contacts and an actuator for actuating themovable contacts the combination comprising an insulating supportadapted to be detachably secured to such a main switch with a pair ofhorizontally spaced right and left hand terminal receiving portions,each portion presenting terminal orientating surfaces; a first terminalincluding a central web with top and bottom margins, a first flangeextending from one margin of said web with a fixed contact oflset to oneside of said terminal, a second flange extending from the other marginof said web, and orientation surfaces adapted to mate with theorientat'ing surfaces of said insulating support whereby said terminalmay be inserted in either the right or left hand terminal receivingportion but is restricted such that said contact is (lisp sed toward thetop and the outside when in the right hand terminal receiving portionand toward the bottom and outside when in the left hand terminalreceiving portion; a second terminal with a central web with top andbottom margins, a first flange extending from one margin of said webwith a fixed contact offset to one side of said terminal, a secondflange extending from the other margin of said web, and orientationsurfaces adapted to mate with the orientating surfaces of saidinsulating support whereby said terminal may be inserted in either theright or left hand terminal receiving portion but is restricted suchthat said contact is disposed toward the bottom and outside when in theright hand terminal receiving portion and toward the top and outsidewhen in the left hand terminal receiving portion; attachment meansadapted to engage the lowermost flange of each terminal to said support;an operating member pivoted at one end to said support and extendingbetween said terminals to a deflectable end for movement by the actuatorof a main switch; and a resilient deflectable bridging contact armcarried by said operating member extending between the contacts of saidterminals for engagement and disengagement therewith.

10. In a detachable auxiliary contact switch for a main switch having acontact hood with top, sides, back and front that is open at the bottom;stationary contacts within the hood; movable contacts; and an actuatorbeneath the hood supporting the movable contacts movable toward and awayfrom the stationary contacts, the combination comprising an insulatingsupport with an upper attachment portion adapted to be fastened to thefront of the hood of a main switch and a depending portion to turnbeneath the front of the hood which forms a housing and is closed at thesides, bottom and top; terminal means enclosing the front of saidhousing presenting fixed contacts within the housing; a lever pivoted atthe forward end to said housing at a point to the front of said fixedcontacts extending rearwardly of said housing into the path of travel ofthe actuator of the main switch to which the auxiliary contact switchmay be attached; a bias spring carried by said housing urging said leverto pivot in a direction corresponding to Contact open position of anactuator; and movable contact means carried by said lever in facingrelation to said fixed contacts within the housing.

11. In a detachable auxiliary contact switch for a main switch thelatter having a contact hood with a top, sides, back and front that isopen at the bottom; stationary contacts within the hood; movablecontacts; and an actuator beneath the hood supporting the movablecontacts which is reciprocably movable between normal and actuatedpositions; the combination comprising an insulating support with anupper attachment portion adapted to be fastened to the front of the hoodof the main switch and a depending portion to turn beneath the front ofthe hood which includes an auxiliary contact housing; terminal meansaccessible from the exterior of the housing and extending to within thehousing to present fixed auxiliary contacts therein; a lever pivoted tosaid insulating support and extending rearwardly of said housing intothe path of travel of the actuator of the main switch to be operativelyengaged thereby; a bias spring carried by said insulating support urgingsaid lever to pivot in a direction corresponding to normal position ofthe actuator; and movable contact means carried by said lever in facingrelation to said fixed auxiliary contacts within the housing.

References Cited in the file of this patent UNITED STATES PATENTS2,190,299 Van Valkenburg Feb. 13, 1940 2,239,031 Bierenfeld et al Apr.22, 1941 2,295,577 Hammerly Sept. 15, 1942 2,297,339 Wilms et a1 Sept.29, 1942 2,360,670 Goetz Oct. 17, 1944 2,481,431 Logan Sept. 6, 19492,500,181 Hubbell et al Mar. 14, 1950 2,545,986 Basnett Mar. 20, 19512,585,824 Noyes Feb, 12, 1952 FOREIGN PATENTS 120,261 Sweden Nov. 25,1947 633,396 Great Britain Dec. 12, 1949

